Gravel Calculator - Tonnes & Volume
Calculate exactly how much gravel, decorative stone, or aggregate you need for your UK landscaping project. Our free calculator works out the volume in cubic metres and weight in tonnes, plus how many bags or bulk bags you'll need. Whether you're creating a gravel driveway, garden path, decorative border, or patio area, get accurate measurements to order the right amount.
Quick Reference: Coverage per Tonne
Calculate Gravel Required
How to Calculate Gravel Needed
Calculating the amount of gravel required is straightforward: work out the volume in cubic metres, then convert to weight using the gravel's density.
The Calculation Formula
Volume (m³) = Length (m) × Width (m) × Depth (m)
Step 2: Convert to Tonnes
Weight (tonnes) = Volume (m³) × Density (t/m³)
Step 3: Add wastage
Final amount = Weight × 1.10 (for 10% extra)
Example: Garden Path
Project: Path 10m × 1m, 50mm depth, pea gravel
- Area: 10m × 1m = 10 m²
- Volume: 10 × 0.05 = 0.5 m³
- Weight: 0.5 × 1.6 = 0.8 tonnes
- Plus 10%: 0.88 tonnes
- Order: 1 tonne
Example: Driveway
Project: Drive 6m × 3m, 75mm depth, 20mm gravel
- Area: 6m × 3m = 18 m²
- Volume: 18 × 0.075 = 1.35 m³
- Weight: 1.35 × 1.7 = 2.3 tonnes
- Plus 10%: 2.53 tonnes
- Order: 2.5-3 tonnes
Always Add Extra
Always order 10-15% more than calculated. Gravel compacts when walked on, some is lost during spreading, and ground is rarely perfectly level. It's better to have some left over than to run short mid-project.
Types of Gravel Available in the UK
There's a wide variety of gravel, stone, and aggregate available in the UK. Here are the most popular options for different applications:
20mm Gravel
Best for: Driveways
Angular, compacts well
Density: 1.7 t/m³
£35-£50/tonne
Pea Gravel (10mm)
Best for: Paths, borders
Rounded, smooth underfoot
Density: 1.6 t/m³
£40-£60/tonne
Golden Gravel
Best for: Decorative areas
Warm honey tones
Density: 1.65 t/m³
£50-£70/tonne
Slate Chippings
Best for: Modern gardens
Blue/grey tones, flat
Density: 1.5 t/m³
£60-£90/tonne
Cotswold Chippings
Best for: Traditional gardens
Warm cream/buff colour
Density: 1.65 t/m³
£55-£75/tonne
MOT Type 1
Best for: Sub-base layer
Crushed limestone/granite
Density: 1.8 t/m³
£25-£40/tonne
Gravel Density & Coverage Table
| Gravel Type | Density (t/m³) | Coverage at 50mm | Coverage at 75mm | Best Uses |
|---|---|---|---|---|
| Standard 20mm gravel | 1.7 | ~12 m²/t | ~8 m²/t | Driveways, parking areas |
| Pea gravel (10mm) | 1.6 | ~12.5 m²/t | ~8.3 m²/t | Paths, playgrounds |
| Golden gravel | 1.65 | ~12 m²/t | ~8 m²/t | Decorative borders |
| Slate chippings | 1.5 | ~13 m²/t | ~9 m²/t | Rockeries, modern gardens |
| Cotswold chippings | 1.65 | ~12 m²/t | ~8 m²/t | Traditional cottage gardens |
| MOT Type 1 | 1.8 | ~11 m²/t | ~7.5 m²/t | Sub-base only (not decorative) |
| Scottish cobbles | 1.4 | ~14 m²/t | ~9.5 m²/t | Large decorative features |
| White marble chips | 1.5 | ~13 m²/t | ~9 m²/t | Contemporary gardens |
Recommended Gravel Depths
Getting the depth right is important for both appearance and function. Too shallow and you'll see the membrane or ground through; too deep wastes money.
| Application | Minimum | Recommended | Notes |
|---|---|---|---|
| Decorative plant borders | 25mm | 30-40mm | Top up as needed annually |
| Garden paths (foot traffic) | 40mm | 50mm | With weed membrane |
| Patio surround | 30mm | 40-50mm | Level with patio edge |
| Light-use driveway | 50mm | 75mm | On compacted sub-base |
| Vehicle driveway | 75mm | 75-100mm | 100-150mm sub-base essential |
| Resin-bound gravel | 15mm | 18-25mm | Different product type |
Driveway Construction Layers (UK Standard)
A proper gravel driveway should consist of multiple layers:
- Excavate: Remove 150-200mm of topsoil
- Geotextile membrane: To prevent sub-base mixing with soil
- Sub-base: 100-150mm compacted MOT Type 1
- Weed membrane: Heavy-duty landscape fabric
- Surface gravel: 75-100mm decorative gravel
- Edging: Metal, timber, or brick to retain gravel
UK Gravel Prices (2024-2025)
Gravel prices vary by type, quantity, and supplier. Bulk delivery is significantly cheaper than bags from DIY stores.
Bulk Delivery Prices (Per Tonne)
Standard 20mm Gravel
£35-£50 per tonne
Most economical option
Pea Gravel (10mm)
£40-£60 per tonne
Popular for paths
Decorative Gravel
£50-£80 per tonne
Golden, Cotswold, etc.
Slate Chippings
£60-£100 per tonne
Premium option
Bag vs Bulk Comparison
| Option | Price | Coverage | Cost per m² at 50mm |
|---|---|---|---|
| 25kg bags (DIY store) | £4-£6 per bag | ~0.015 m³/bag | £13-£20/m² |
| Bulk bags (850kg) | £40-£70 per bag | ~0.5 m³/bag | £4-£7/m² |
| Loose bulk (per tonne) | £35-£60 + delivery | ~0.6 m³/tonne | £2.90-£5/m² |
Cost Comparison: Covering 20m² at 50mm Depth
Amount needed: ~1.7 tonnes (including 10% extra)
| 25kg bags from B&Q/Wickes: | ~68 bags × £5 = £340 |
| Bulk bags from builders merchant: | 2 bags × £55 = £110 |
| Loose delivery: | 2 tonnes × £45 + £80 delivery = £170 |
For anything over 0.5 tonnes, bulk delivery or bulk bags save significant money.
Delivery Charges
Most suppliers charge £50-£100 for delivery, often with a minimum order of 0.5-1 tonne. Some offer free delivery over certain amounts (typically 5+ tonnes). Always get the total price including delivery before ordering.
How to Lay Gravel: Step-by-Step Guide
Proper preparation is key to a long-lasting gravel surface. Here's how to lay gravel correctly.
Basic Steps for Garden Paths and Borders
- Mark out the area: Use string lines or spray paint
- Excavate: Remove 75-100mm of soil for paths (less for decorative borders)
- Compact the base: Use a hand tamper or whacker plate
- Lay weed membrane: Overlap sheets by 150mm
- Install edging: This contains the gravel
- Spread gravel: Use a rake to level
- Compact if needed: For driveways, lightly compact with a roller
Weed Membrane Guide
| Membrane Type | Weight | Use | Price |
|---|---|---|---|
| Light-duty | 50 g/m² | Decorative borders only | £0.50-£1/m² |
| Medium-duty | 100 g/m² | Paths and patios | £1-£2/m² |
| Heavy-duty | 150+ g/m² | Driveways, high traffic | £2-£4/m² |
For Driveways: Consider Gravel Grids
Honeycomb-style plastic grids (like GravelGrid, Core Drive, or Permeable Eco) lock gravel in place, preventing it from shifting under vehicle tyres. They also improve drainage and reduce gravel spreading onto lawns. Typical cost: £8-£15 per m².
Planning Permission for Gravel Driveways
Good news for homeowners: gravel driveways usually don't require planning permission in England.
Why Gravel is Usually Permitted
Since 2008, new driveways using impermeable materials (concrete, tarmac) over 5m² require planning permission unless they drain properly. However, loose gravel is considered a permeable surface because water can drain through it into the ground below.
When You Might Need Permission
- If your property is listed
- If you're in a conservation area (check local rules)
- If there are restrictive covenants on your property
- If you're changing the access point to a classified road
- If you're within Article 4 Direction areas
Always check with your local planning authority if unsure.
Dropped Kerb
If you're creating a new driveway with vehicle access, you'll likely need a dropped kerb. This requires permission from your local council highways department and typically costs £800-£2,000 in the UK. The council may do the work themselves or give permission for an approved contractor.
Frequently Asked Questions
Click on a question to reveal the answer.
How much gravel do I need for a driveway?
For a standard UK driveway, use 75mm depth. A single-car driveway (3m × 6m = 18m²) needs approximately 1.35m³ or 2.3 tonnes of gravel. Add 10% for compaction, so order about 2.5-3 tonnes. Use 20mm angular gravel for best results under vehicle tyres.
How much does a tonne of gravel cover?
One tonne of standard gravel (1.7t/m³ density) covers approximately 12m² at 50mm depth, 10m² at 60mm depth, or 8m² at 75mm depth. Lighter stones like slate cover more area per tonne due to lower density.
What depth of gravel do I need?
25-40mm for decorative borders, 50mm for paths, 75-100mm for driveways. Deeper is better for vehicle traffic to prevent rutting. Always lay on compacted sub-base for high-traffic areas.
How much does gravel cost in the UK?
Bulk delivery: £35-£80 per tonne depending on type, plus £50-£100 delivery. Bagged from DIY stores costs around £4-£6 per 25kg bag (much more expensive per tonne). For anything over 0.5 tonnes, bulk delivery is more economical.
Do I need a sub-base under gravel?
For driveways: Yes, 100-150mm of compacted MOT Type 1 is essential. For paths: Recommended but not essential if on stable ground. For borders: Not usually needed - just use weed membrane.
What size gravel is best for a driveway?
20mm angular gravel is ideal - it compacts well and stays in place. Avoid pea gravel (10mm rounded) as it shifts under tyres. Some people layer 20mm as base with 10mm on top for smoother walking.
Do I need planning permission for a gravel driveway?
Usually no - gravel is a permeable surface so the 5m² rule for impermeable driveways doesn't apply. However, check with your local authority if you're in a conservation area, have a listed building, or need a new dropped kerb.
How do I stop gravel spreading?
Use proper edging (metal strips, timber, brick, or plastic) to contain the gravel. For driveways, gravel grids (honeycomb mats) lock stones in place and prevent them spreading under vehicle tyres. Popular UK brands include Core Drive and GravelGrid.
James Mitchell
Landscape Designer & Contractor
BALI Registered | RHS Qualified | 22 years experience
James has designed and installed over 500 gardens across the UK, specialising in sustainable landscaping, permeable surfaces, and gravel garden design. Member of the British Association of Landscape Industries.
Related Construction Calculators
Last updated: December 2025 | Prices verified against Jewson, Travis Perkins, and Wickes. Calculations based on UK aggregate industry standards.
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Understanding Your Results
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- 2025/26 updated - Using current rates and regulations
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